<div>
	<el-dropdown :hide-on-click="false" trigger="click">
		<slot>
			<el-button>显示列<span class="icon eliconfont icon-gear"></span></el-button>
		</slot>
		<el-dropdown-menu slot="dropdown">
			<div style="max-height: 300px;overflow: auto;">
				<el-checkbox-group v-model="checkList" @change="change">
					<el-dropdown-item v-for="(column,index) in showColumns">
						<el-checkbox  :label="column.title" :key="index"></el-checkbox>
					</el-dropdown-item>
				</el-checkbox-group>
			</div>
		</el-dropdown-menu>
	</el-dropdown>
</div>